Generators are used in a variety of different environments. For example, a generator can be used as a secondary or back-up power source for a building (e.g., a residence) or as the primary power source at a construction site. Numerous other situations or uses for a generator are possible.
Bonding the neutral wire of the generator to ground is required in some environments. For example, the U.S. Occupational Safety & Health Administration (OSHA) requires industrial (also referred to as commercial) generators to be neutral bonded, i.e., electrically connecting the neutral wire of the generator to ground. Also, it is typically required to include a ground-fault-circuit interrupt (GFCI) in the industrial generator for detecting ground-fault current.
A breaker box of a building or residence also typically has the neutral wire bonded to ground. If the industrial generator is connected to such a breaker box, a loop is created with the neutral wire of the industrial generator and the ground wire of the breaker box. This potentially induces a current through the neutral and ground wires, which trips the GFCI of the industrial generator.